JP3470651B2 - Manufacturing method of ceramic electronic component - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a ceramic electronic component, and more particularly, it is manufactured through a process of subjecting a ceramic element constituting the ceramic electronic component to a process for causing adhesion or adsorption of moisture. The present invention relates to a method for manufacturing a ceramic electronic component.

[0002]

2. Description of the Related Art For example, as shown in FIG. 1, a multilayer ceramic capacitor, which is one of typical ceramic electronic components, has a plurality of internal electrodes 1 with ceramic layers 2 interposed therebetween. External electrodes 4a and 4b are provided so as to be electrically connected to the internal electrode 1 on a ceramic element 5 which is arranged so as to face each other and has a structure in which the opposite end surfaces 3a and 3b are alternately drawn out. It has a structure.

By the way, the monolithic ceramic capacitor as described above may be manufactured, for example, through the steps described below.

(1) An electrode printed sheet is formed by printing a conductive paste that will become internal electrodes on the surface of a ceramic green sheet. (2) A predetermined number of the electrode printed sheets and the ceramic green sheets (cover sheets on the upper and lower sides) on which the conductive paste is not printed are laminated and pressure-bonded to form a laminated pressure-bonded body. (3) Then, the laminated pressure-bonded body is cut at a predetermined position to cut out each unfired ceramic element, and then the ceramic element is sintered at a predetermined temperature. (4) Next, the ceramic element is put into a barrel together with a mixture of water and a polishing medium, and the surface is polished by stirring, so-called wet barrel polishing treatment is performed to polish the surface of the ceramic element and chamfer it. (5) Then, the ceramic element 5 is coated with a conductive paste and baked to form external electrodes. As a result, a monolithic ceramic capacitor as shown in FIG. 1 is obtained.

In the above conventional manufacturing method, however, the ceramic element adsorbs water in the barrel polishing step (4) , and the conductive paste is converted into the ceramic element in the subsequent external electrode forming step (5) . There is a problem that it causes a so-called repellency phenomenon, which makes it difficult to get on the surface.

Further, depending on the type of ceramic electronic component, Ni plating and Sn plating (solder plating) may be applied to the surface of the external electrode in order to improve connection reliability and solderability. However, in such a case, the plating solution soaks into the ceramic element, and the water in the plating solution evaporates in the process of mounting on a circuit board by a method such as reflow soldering, causing solder solder (burst). Occurs, and a solder bridge is generated between adjacent electronic components, which causes a short circuit.

The present invention solves the above problems, and repels the conductive paste when the moisture is efficiently evaporated from the ceramic element to be removed, and the conductive paste is applied and baked to form the external electrodes. Also, it is possible to prevent solder from soldering at the time of mounting due to the adhesion or adsorption of the plating solution when plating the external electrodes, and it is possible to efficiently manufacture highly reliable ceramic electronic components. It is an object to provide a method for manufacturing an electronic component.

[0008]

To achieve the above object, according to the Invention The production method of a ceramic electronic component of the present invention, the outside surface of the ceramic element made by firing a ceramic molded body
And forming an electrode, the outer and facilities the wet plating process
Forming a plating film on the surface of the internal electrode,
By heating the ceramic element plated film is formed on the electrode surface above 120 ° C. under reduced pressure, it is characterized by comprising the step of removing moisture from the ceramic element.

After forming the external electrodes on the ceramic element ,
Wet plating to form a plating film on the surface of the external electrode.
In the step of performing came, although adhesion or adsorption of the plating solution into the ceramic element is produced, the ceramic element under reduced pressure 120
By heating at a temperature of not less than 0 ° C, it becomes possible to reliably and efficiently remove the water contained in the plating solution from the ceramic element. Therefore, when a ceramic electronic component is mounted on a circuit board, etc. by a method such as reflow soldering, the evaporation of water from the plating solution causes the solder to stick (explode) and short-circuit with the adjacent electronic component. It is possible to prevent the occurrence of the occurrence, and it is possible to efficiently manufacture a highly reliable ceramic electronic component.

In the method of manufacturing a ceramic electronic component according to a second aspect of the present invention, the ceramic element is a laminated ceramic element having a laminated structure in which a plurality of internal electrode layers are arranged with a ceramic layer inside. It is characterized by being.

A laminated ceramic element having a laminated structure in which a plurality of internal electrode layers are arranged with a ceramic layer inside is likely to cause moisture adsorption during the wet plating process and cause its adverse effects. However, according to the method of the present invention, it becomes possible to efficiently remove water and efficiently prevent the occurrence of defects due to the adsorption of water. Therefore, the present invention is particularly significant when applied to a method for manufacturing a monolithic ceramic electronic component such as a monolithic ceramic capacitor or a monolithic varistor.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be shown below, and the characteristic features thereof will be described in more detail.

[ Reference Embodiment] In this reference embodiment, as a ceramic electronic component, as shown in FIG. 1, a plurality of internal electrodes 1 are arranged so as to face each other with a ceramic layer 2 interposed therebetween, and alternate. A ceramic element 5 having a structure extended to the opposite end faces 3a and 3b is connected to the external electrode 4 so as to be electrically connected to the internal electrode 1.
A case of manufacturing a monolithic ceramic capacitor having a structure in which a and 4b are arranged will be described as an example.

(1) First, a conductive paste to be internal electrodes is printed on the surface of a ceramic green sheet to form an electrode printed sheet. (2) A predetermined number of the electrode printed sheets and the ceramic green sheets (cover sheets on the upper and lower sides) on which the conductive paste is not printed are laminated and pressure-bonded to form a laminated pressure-bonded body. (3) Then, the laminated pressure-bonded body is cut at a predetermined position to cut out each unfired ceramic element, and then the ceramic element is sintered at a predetermined temperature. (4) Next, the ceramic element is put into a barrel together with water or a mixture of water and a polishing medium and stirred, whereby the surface of the ceramic element is polished and chamfered. (5) Then, after the ceramic element is washed with water, hot air blown to a predetermined temperature is blown while vacuum suction to evaporate and remove the water adhering to the surface of the ceramic element and the water adsorbed inside. To do. (6) Then, a conductive paste (Ag paste in this reference embodiment) is applied to the ceramic element 5 from which the moisture has been removed as described above and baked to form an external electrode. As a result, a monolithic ceramic capacitor as shown in FIG. 1 was obtained.

In this reference embodiment, conditions (vacuum degree and temperature) as shown in test numbers 4, 5, and 6 of Table 1 are used.
Then, the ceramic element was dried. In addition, for comparison, the ceramic element was also tested under the condition that only hot air was blown and vacuum suction was not performed (test numbers 1 and 2 in Table 1) and the condition that only vacuum suction was used and heating was not performed (test number 3). It was dried.

With respect to the obtained laminated ceramic capacitor, the state of the external electrodes was observed, and the occurrence of a so-called repellency phenomenon in which the conductive paste was less likely to adhere to the surface of the ceramic element (a repulsion phenomenon for 500 samples) The number of The results are also shown in Table 1.

[0017]

[Table 1]

From Table 1, it is found that the repelling phenomenon occurred at a considerable rate when dried under the conditions (test numbers 1 and 2) in which only hot air was blown and vacuum suction was not performed. It is considered that this is because the moisture adsorbed inside is less likely to evaporate because vacuum suction is not performed.

Also, when the sample was dried under the condition that only vacuum suction was performed and heating was not performed (test number 3), the repelling phenomenon occurred at a high rate of 25 per 500 samples. It is considered that this is because even if vacuum suction is performed, if the temperature is room temperature, the moisture cannot be sufficiently evaporated, and the moisture adsorbed inside is difficult to remove.

On the other hand, in the case of the method according to the reference embodiment in which hot air is blown while vacuum suction is performed (test numbers 4, 5 and 6), the degree of vacuum is 133 Pa and the temperature (hot air blowing temperature) is 150 ° C. × 2. In the time, the number of repellency phenomena was as small as 6 per 500 samples, and the degree of vacuum was 133 Pa, the temperature (hot air blowing temperature) was 200 ° C. × 2 hours, and the degree of vacuum was 133 Pa, the temperature was 300 ° C. × 2 hours. No repulsion phenomenon was observed. It is considered that this is because the hot air is blown while vacuum suction, so that the drying is sufficiently performed and the moisture is sufficiently removed from the ceramic element.

[Embodiment of the Present Invention] In this embodiment, in order to improve the solderability of the product, the wet process is performed on the surface of the external electrode (Ag electrode) of the multilayer ceramic capacitor manufactured by the method of the reference embodiment. By performing plating to form a Ni plating film and further forming a Sn plating film on the Ni plating film, washing with water, vacuum suction, and blowing with warm air of a predetermined temperature to dry , As shown, a plurality of internal electrodes 1
Are arranged so as to face each other with the Mick layer 2 in between,
The structure drawn alternately to the opposite end faces 3a, 3b.
Conducting electrical connection with the internal electrode 1 to the ceramic element 5 that it has.
External electrodes 4a, 4b to obtain a multilayer ceramic capacitor (final product) having arranged structure on.

[0022] In this embodiment, as in the case of the referential embodiment, after performing the wet barrel polishing treatment, dried by heating to a predetermined temperature while sucking in vacuum, repelling A multilayer ceramic capacitor having an external electrode formed by applying and baking a conductive paste without causing a phenomenon was used, and the surface of the external electrode was subjected to wet plating to form a Ni plating film and a Sn plating film.

Further, in this embodiment, when the laminated ceramic capacitor (ceramic element) is dried after the wet plating, it is dried under the conditions (vacuum degree and temperature) shown in the test numbers 5, 6, and 7 of Table 2. went. In addition, for comparison, under the condition that only vacuum suction is performed and heating is not performed (test numbers 1 and 2 in Table 2) and the condition that only hot air is blown and vacuum suction is not performed (test number 3 and 4), The monolithic ceramic capacitor was dried.

Then, the obtained monolithic ceramic capacitor was mounted on a circuit board by a reflow soldering method, and the occurrence state of solder solder (burst) was observed. The results are also shown in Table 2.

[0025]

[Table 2]

From Table 2, when dried under the conditions of vacuum suction but no heating (Test Nos. 1 and 2), solder crease (burst) occurred at a high rate. This is because if hot air is not blown even if vacuum suction is performed,
It is considered that this is because the water cannot be sufficiently evaporated and the water adsorbed inside is difficult to remove.

Further, even when only the hot air was blown and the vacuum suction was not performed (Test Nos. 3 and 4), a considerable amount of solder broke (rupture) occurred.
It is considered that this is because even if the hot air is blown, the moisture cannot be sufficiently evaporated without vacuum suction, and the moisture adsorbed inside is difficult to be removed.

On the other hand, with vacuum suction, in the case of the method according to the exemplary shaped state of the present invention conducted the blowing of warm air (Test No. 5, 6 and 7), significantly the occurrence of solder goby (rupture) You can see that it is decreasing. It is considered that this is because hot air is blown while vacuum suction is performed, so that the ceramic element is sufficiently dried and moisture is sufficiently removed.

[0029] Oite to the above embodiment, the case of producing a multilayer ceramic capacitor was explained as an example, the present invention is not limited to a multilayer ceramic capacitor, various formed by disposing the external electrode on the surface of the ceramic element It can be widely applied to the production of the ceramic electronic component.

Further, the present invention is not limited to the above embodiment in other points as well, and the degree of vacuum,
Various applications and modifications can be made within the scope of the invention with respect to the drying conditions such as temperature and time, the type of ceramic that constitutes the ceramic element, the constituent material and structure of the external electrode, and the like.

[0031]

As described above, according to the method for manufacturing a ceramic electronic component of the present invention (claim 1), a ceramic element is formed.
Wet plating treatment is applied to the surface of the external electrode
After forming the membrane, the ceramic element is put under reduced pressure at 120 ° C.
Since the heating is performed as described above, it becomes possible to reliably remove the moisture from the ceramic element . As a result,
When a ceramic electronic component is mounted on a circuit board, etc. by a method such as reflow soldering, the evaporation of water from the plating solution causes the solder to fit (explode) and cause a short circuit with the adjacent electronic component. It becomes possible to prevent the occurrence of the occurrence, and it becomes possible to efficiently manufacture a highly reliable ceramic electronic component.

Further, a laminated ceramic element having a laminated structure in which a plurality of internal electrode layers are arranged with ceramic layers interposed therein is used in the process of applying wet plating to the external electrodes . Although adsorption is likely to occur and its adverse effect is likely to occur, the method of the present invention (Claim 2 ) makes it possible to efficiently remove water and efficiently prevent the occurrence of defects due to water adsorption. . Therefore, the present invention is particularly significant when applied to a method for manufacturing a laminated ceramic electronic component such as a laminated ceramic capacitor or a laminated varistor.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a monolithic ceramic electronic component (multilayer ceramic capacitor) manufactured in an embodiment of the present invention.

[Explanation of symbols]

1 internal electrode 2 ceramic layers 3a, 3b end faces 4a, 4b external electrodes 5 Ceramic element

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 10-166302 (JP, A) JP 4-250607 (JP, A) JP 11-244216 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H01G 4/00-4/42

Claims (2)

(57) [Claims] 1. A ceramic formed by firing a ceramic molded body.
ElementSurface ofToA step of forming an external electrode, Wet plating ProcessedThen, a plating film is formed on the surface of the external electrode.
A step of forming A plating film was formed on the surface of the external electrode ceramic
Under reduced pressureAbove 120 ° CBy heating,
Process to remove water from Lamic elementWhenTo have
A method for manufacturing a ceramic electronic component, comprising: 2. The ceramic electronic device according to claim 1, wherein the ceramic element is a laminated ceramic element having a laminated structure in which a plurality of internal electrode layers are arranged with a ceramic layer interposed therebetween. Manufacturing method of parts.